Heat exchanger, in particular for a refrigerant circulating in a motor vehicle

ABSTRACT

A heat exchanger for a refrigerant circulating in a motor vehicle is disclosed. The exchanger has a first unit for circulating a first fluid defining first blades for circulating the first fluid and a second unit for circulating a second fluid defining second blades for circulating the second fluid. The blades are layered in a stacking direction of said blades such that an exchange of heat can take place between the first and second fluids, where the units permit the first fluid to circulate while avoiding the second unit, and permitting the second fluid to circulate while avoiding the first unit.

The invention relates to an exchanger. Although intended more specifically for applications as an internal exchanger of an air conditioning circuit or as an exchanger between a refrigerant and a heat transfer fluid, it may also be utilized more broadly for any type of exchange of heat between two fluids.

Numerous configurations of exchangers defining circulation blades for each of the fluids, between which the exchange of heat is required to take place, are known in this field. Brazed exchangers in which the blades are defined by stacked plates, between which the circulation blades are defined alternately, are particularly well known. The blades for the circulation of fluid are joined together by connection elements discharging in the area of passage openings that are likewise provided in the plates in such a way that each fluid passes from one of its circulation blades to the other without penetrating into the circulation blades of the other fluid. The circulation blades of each of the fluids are thus traversed by the connection elements of the other fluid.

Such a configuration multiplies the brazing zones, in particular in the area of the junction between the connection elements and the passage openings of the neighboring plates. It also multiplies the risks in terms of the sealing between each of the fluid circuits. Specific sealing tests are thus necessary.

Furthermore, the zones of the plates that are equipped with said connection elements contribute not at all or only a little to the exchange of heat. As a result, they increase the cost of the exchanger because of the mass of material employed, yet without improving the efficiency of the thermal exchange.

The object of the invention is to address the aforementioned disadvantages, and in this respect it proposes a heat exchanger, in particular for a refrigerant circulating in a motor vehicle, said exchanger comprising a first unit for circulating a first fluid defining first blades for circulating said first fluid and a second unit for circulating a second fluid defining second blades for circulating said second fluid, said blades being layered in a stacking direction of said blades such that an exchange of heat can take place between said first and second fluids. According to the invention, said units permit the first fluid to circulate while avoiding the second unit, and permit the second fluid to circulate while avoiding the first unit.

In other words, the exchanger is configured in order for the units to be interleaved one inside the other in such a way as to ensure an exchange of heat between the two fluids, but without the first fluid passing though components of the second unit and without the second fluid passing through components of the first unit.

Such a configuration in the form of units makes it possible to avoid causing connection elements between the blades for the circulation of one of the fluids to pass across the blades for the circulation of the other fluid. The zones to be brazed are reduced in this way, and the risks of leakage from one circuit for the circulation of a fluid to the other are limited. The test procedures may be simplified as a result. The zones of circulation blades which serve not at all or very little for the exchange of heat are reduced in addition.

According to different embodiments, which may be taken together or separately:

-   -   said blades extend in a longitudinal direction, perpendicular to         the stacking direction,     -   said first unit comprises collectors for the first fluid,         situated in the area of a longitudinal end edge of the blades of         said first unit, and/or said second unit comprises collectors         for the second fluid, situated in the area of a longitudinal end         edge of the blades of said second unit,     -   said blades are configured in order to cause a U-shaped circuit         to be made for the fluid between a first of said collectors and         a second of said collectors of the corresponding unit,     -   the collectors of the first unit are situated facing a         longitudinal end edge of the blades of the second unit, opposite         the longitudinal end edge of the blades of the second unit, in         the area of which said collectors of the second unit are         present,     -   the collectors of the second unit are situated facing a         longitudinal end edge of the blades of the first unit, opposite         the longitudinal end edge of the blades of the first unit, in         the area of which said collectors of the first unit are present,     -   the one and/or the other of said units comprises plates, stacked         in said stacking direction, said plates being paired in order to         define said circulation blades, for the one and/or the other of         the fluids,     -   the pairs of plates for each of the fluids exhibit a part         protruding from the pairs of plates for the other fluid, in         planes that are orthogonal to said stacking direction, in such a         way as to be able to free up a zone of said plates, referred to         as header plates, for receiving said collectors,     -   said exchanger comprises fluid connections between the plates of         the pairs of plates for a same fluid, situated in the area of         said header plates, in such a way as to form said collectors,     -   said connections are situated externally to the pairs of plates         for said other fluid,     -   said fluid connections comprise stamped end fittings emerging         from said plates, said stamped end fittings coming into contact         with the stamped end fittings of the plate facing the         neighboring pair of plates for the circulation of the same         fluid,     -   said plates comprise a longitudinal end edge, referred to as the         distal edge, opposite an opposing longitudinal end edge of said         plates, in the area of which said fluid connections are         situated, said distal edge being situated between two plates         facing two neighboring pairs of plates for the circulation of         the other fluid,     -   said distal edge of the plates of one of the units is in         proximity to said fluid connections of the other unit, and         conversely,     -   said distal edge includes a part of the contour of said fluid         connections,     -   said blades comprise a means of disrupting the flow of the first         and/or of the second fluid, such a means being of the stamped         plate type, for example, referred to in this case as a baffle,         which is capable of being integrated into a circuit for the flow         of the first and/or of the second fluid,     -   the second unit comprises at least one pair of terminating         plates, in said stacking direction, comprising one plate         exhibiting a longitudinal extension identical to the other         plates of said unit and one terminating plate exhibiting an         upper longitudinal extension,     -   said second unit comprises at least one connecting flange for         one of the fluids that is subject to said terminating plate.

The invention further relates to an exchanger unit such as the one or the other of the units of the exchanger described above.

Said unit may be utilized as a functional component either in such an exchanger with interleaved units, or in another type of exchanger.

Said unit may thus be equipped with a spacer between said pairs of plates and may serve, in particular, as an evaporator by exchange with a flow of air.

It may also be inserted in a housing, and the invention further relates to another heat exchanger comprising such a heat exchanger unit and a housing for circulating another fluid, said unit being situated in the interior of said housing in order to permit an exchange of heat between the fluid circulating in said unit and said other fluid.

These and other characterizing features of the present invention are illustrated below with reference to the accompanying drawings, in which:

FIG. 1 is a view in perspective of an embodiment of a heat exchanger consistent with the invention;

FIG. 2 is a view in perspective, partially exploded, of the exchanger in FIG. 1;

FIG. 3 is a view in perspective of a first plate of the exchanger in FIG. 1;

FIG. 4 is a view in perspective of another plate of the exchanger in FIG. 1;

FIG. 5 is a side view of one of the fluid circulation units of the exchanger in FIG. 1, equipped with a fluid connection flange;

FIG. 6 is a side view of the other of the fluid circulation units of the exchanger in FIG. 1, equipped with a single fluid connection flange; and

FIG. 7 is a side view of an exchanger utilizing the unit in FIG. 5, in this case equipped with a supplementary component.

In the following description, identical references are used to designate the same or similar elements.

As illustrated in FIGS. 1 and 2, the invention relates to a heat exchanger, in particular for a refrigerant circulating in a motor vehicle.

Said exchanger comprises a first unit 1 for circulating a first fluid defining first blades 3 for circulating said first fluid and a second unit 2 for circulating a second fluid defining second blades 4 for circulating said second fluid. Said blades 3, 4 are layered in a stacking direction D of said blades, such that exchange of heat can take place between said first and second fluids.

Said units 1, 2 are formed, for example, by a component made of aluminum and/or an aluminum alloy. They can be assembled, for example, by brazing of said components.

In FIG. 1, said first unit 1 extends from the top towards the bottom, while the second unit 2 extends from the bottom towards the top. An example of the circulation of the fluid in the blades of the first unit 1 is illustrated by the arrows 1 a, 1 b, 1 c, while an example of the circulation of the fluid in the blades of the second unit 2 is illustrated by the arrows 2 a, 2 b, 2 c, on the right in the figure.

According to a first illustrative embodiment, said heat exchanger may be an internal exchanger of an air conditioning circuit. In other words, said first and second fluids may be a fluid known as R134a or R1234yf, inter alia, such that the first unit 1 serves for the circulation of the fluid in a first temperature and pressure condition, and the second unit 2 serves for the circulation of the fluid in a second temperature and pressure condition.

In another illustrative embodiment, said exchanger ensures an exchange of heat between said refrigerant and a heat transfer fluid, such as a mixture of water and antifreeze, in particular glycol. According to the nature of the refrigerant fluid, this may then result in the cooling or heating of the heat transfer fluid.

Other applications are still possible, however.

According to the invention, said units 1, 2 permit the first fluid to circulate while avoiding the second unit 2 and permit the second fluid to circulate while avoiding the first unit 1. In other words, the exchanger is configured in order for the units to be interleaved one inside the other, in this case such as two combs, but without the first fluid passing through components of the second unit 2 and without the second fluid passing through components of the first unit 1. It is possible in this way to obtain an exchange of heat between the two fluids while avoiding the more complex flows of the state of the art.

Such interleaving will be more readily appreciated from an examination of FIGS. 5 and 6, but without taking into account the mounting flanges 100, 200 that are present in these figures. FIG. 5 shows the first unit 1, in this case serving for the circulation of a refrigerant fluid. FIG. 6 shows the second unit 2, in this case serving for the circulation of a heat transfer fluid. It will thus be appreciated that the exchanger in FIGS. 1 and 2 results from the interleaving of the units 1, 2 in each of these figures.

Again making reference to FIGS. 1 and 2, it will be observed that said blades 3, 4 in this case extend in a longitudinal direction L, perpendicular to the stacking direction D. Said first unit 1 may comprise collectors 5 a, 5 b for the first fluid, situated in the area of a longitudinal end edge 7 of the blades 3 of said first unit 1. Said second unit 2, for its part, may comprise collectors 6 a, 6 b for the second fluid, situated in the area of a longitudinal end edge 8 of the blades 4 of said second unit 1.

As illustrated by the arrows 1 a, 1 b, 1 c and 2 a, 2 b, 2 c mentioned above, said blades are configured in this case in order to cause a U-shaped circuit to be made for said fluid between a first 5 a, 6 a of said collectors and a second 5 b, 6 b of said collectors of the corresponding unit. The first 5 a of the collectors of the first unit 1 thus constitute an inlet collector for the first fluid, while the second 5 b of the collectors of said first unit 1 constitute an outlet collector for said first fluid. Likewise, the first 6 a of the collectors of the second unit 2 constitutes an inlet collector for the second fluid, while the second 6 b of the collectors of said second unit 2 constitutes an outlet collector for said second fluid. In other words, the first fluid circulates in the first unit 1 by being distributed by the inlet collector 5 a of said first unit 1 in the blades 3 of said first unit 1, where it follows the U-shaped circuit 1 a, 1 b, 1 c mentioned above before subsequently penetrating into the corresponding outlet collector 5 b. Likewise, the second fluid circulates in the second unit 2 by being distributed by the inlet collector 6 a of said second unit 2 in the blades 4 of said second unit 2, where it follows the U-shaped circuit 2 a, 2 b, 2 c mentioned above before subsequently penetrating into the corresponding outlet collector 6 b. The circulation of the first fluid in the blades 3 of said first unit 1 takes place co-currently with the circulation of the second fluid in the blades 4 of said second unit 2.

In a variant embodiment (not depicted here), the circulation of the first fluid in the blades 3 of said first unit 1 advantageously takes place contra-currently with the circulation of the second fluid in the blades 4 of said second unit 2.

For the compactness of the exchanger, the collectors 5 a, 5 b of the first unit 1 are situated, for example, facing a longitudinal end edge 10 of the blades of the second unit 2, opposite the longitudinal end edge 8 of the blades 2 of the second units 2, in the area of which said collectors 6 a, 6 b of the second unit 2 are present. Either individually or in combination, the collectors 6 a, 6 b of the second unit 2 are situated facing a longitudinal end edge 9 of the blades 3 of the first unit 1, opposite the longitudinal end edge 7 of the blades 3 of the first unit 1, in the area of which said collectors 5 a, 5 b of the first unit 1 are present.

In other words, said units 1, 2 are mounted head-to-tail. Still in other words, the blades 3, 4 of each of said units 1, 2 are offset in relation to the blades 3, 4 of the other of said units 1, 2 in a direction that is orthogonal to said stacking direction D.

Said units 1, 2 in this case comprise plates 11, 12, stacked in said stacking direction, said plates being paired in order to define said blades 3, 4 and said circuits 1 a, 1 b, 1 c, 2 a, 2 b, 2 c of circulation for each of the fluids. According to other embodiments, said blades may be defined by extruded tubes, bent tubes or any other means permitting the guiding of a fluid.

The pairs of plates 11 for the first fluid exhibit a part 13 protruding from the pairs of plates 12 for the second fluid, in planes that are orthogonal to said stacking direction in such a way as to be able to free up a zone of said plates, referred to as header plates, for receiving said collectors 5 a, 5 b of said first unit 1. Likewise, the pairs of plates 12 for the second fluid exhibit a part 14 protruding from the pairs of plates 11 for the first fluid, in planes that are orthogonal to said stacking direction in such a way as to be able to free up a zone of said plates, referred to as header plates, for receiving said collectors 6 a, 6 b of said second unit 2.

In other words, said pairs of plates 11 for the first fluid are connected to one another without passing through the pairs of plates 12 for the second fluid, and conversely. In other words, said pairs of plates 11 of the first unit 1 are offset in relation to the pairs of plates 12 of the second unit 2, in said longitudinal direction, and conversely.

Said pairs of plates 11, 12 are advantageously identical in the same unit, except perhaps for the one or more pairs of plates including a terminating plate of the stack, as will be described in more detail below.

Said exchanger comprises fluid connections 15 a, 15 b, 16 a, 16 b between the plates 11, 12 of the pairs of plates for the same fluid, situated in the area of said header plates 13, 14, in such a way as to form said collectors 5 a, 5 b, 6 a, 6 b. According to the invention, said connections 15 a, 15 b, 16 a, 16 b for one of the fluids are situated externally to the pairs of plates 11, 12 for the other fluid.

Said fluid connections 15 a, 15 b, 16 a, 16 b comprise, for example, stamped end fittings emerging from said plates 11, 12. Said stamped end fittings 15 a, 15 b of the plates 11 of the first unit 1 in this case come into contact with the stamped end fittings 15 a, 15 b of the plate 11 facing the neighboring pair of plates 11 of said first unit 1. Likewise, said stamped end fittings 16 a, 16 b of the plates 12 of the second unit 2 in this case come into contact with the stamped end fittings 16 a, 16 b of the plate 12 facing the neighboring pair of plates 12 of said second unit 1. Said stamped end fittings are provided with fluid passage openings. Said stamped end fittings 15 a, 15 b, 16 a, 16 b in this way bring about the circulation of fluid from one pair of plates to the other, in the same unit. Said stamped end fittings 15 a, 15 b, 16 a, 16 b of the same collector 5 a, 5 b, 6 a, 6 b are situated in this case in the axial extension one from the other in such a way as to ensure that said collectors are substantially rectilinear. According to the invention, the stamped end fittings of the pairs of plates for the circulation of the first fluid and the stamped end fittings of the pairs of plates for the circulation of the second fluid are situated at two opposite longitudinal extremities of the assembly formed by the two units 1, 2.

Said plates 11, 12 comprise a longitudinal end edge 17, 18, referred to as the distal edge, opposite an opposing longitudinal end edge 19, 20 of said plates, in the area of which said fluid connections 15 a, 15 b, 16 a, 16 b are situated. Said distal edge 17, 18 of the plates 11, 12 for one of the fluids is situated between two facing plates 11, 12 of two neighboring pairs of plates for the circulation of the other fluid.

Said distal edge 17, 18 of the plates 11, 12 of one of the units 1, 2 is in proximity to said fluid connections 15 a, 15 b, 16 a, 16 b of the other unit. In order to ensure good mechanical stability, said distal edge 17, 18 may include a part of the contour of said fluid connections 15 a, 15 b, 16 a, 16 b.

As can be appreciated more readily from FIGS. 3 and 4, said plates 11, 12 of each of the units 1, 2 comprise a base 21, 22, a raised edge 23, 24 and a brazing lip 25, 26. Said pairs of plates are formed by two of said plates, intended to be identical, mounted head-to-tail in such a way that their lips are in contact. Along the distal edge 17, 18 of said plates 11, 12, the brazing lip 25, 26 of the plates of the one of the units 1, 2 is in contact with the stamped end fittings 15 a, 15 b, 16 a, 16 b of the plates of the other unit 1, 2. Said plates of the first and/or of the second unit may also comprise abutments 32 (FIG. 1) extending from said brazing lips 26, in particular in order to facilitate the stacking of said plates before brazing.

Each of said pairs of plates 11, 12 comprises a conduit for the U-shaped circulation of the corresponding fluid, between a first of said collectors 5 a, 6 a permitting the introduction of said fluid into said conduit, and a second of said collectors 5 b, 6 b permitting the exit of said fluid from said conduit.

Said blades 11, 12 may comprise a baffle 27, 28 for the flow of the first and/or of the second fluid. In this case, said baffles define longitudinal channels for the circulation of the first and/or of the second fluid.

According to a variant that is not illustrated here, the desired U-shaped circulation is obtained by a stamped form of the base of the plates such as a partial central rib starting from the longitudinal end edges provided with the connecting stamped end fittings.

According to another variant, corresponding to the illustrated exchanger, the inlet collectors 5 a, 6 a discharge facing towards first parts of channels of the baffles 27, 28, while the outlet collectors discharge facing towards a second part of the channels separated from said first part of the channels 29, 30 by one or a plurality of central channels 29, 30. In addition, said plates 11, 12 comprise blocking stamped end fittings 31, 32, between the connecting stamped end fittings 15 a, 15 b, 16 a, 16 b, closing said one or more central channels 29, 30 at one of their longitudinal ends.

Said baffles 27, 28 are advantageously shorter than the base 21, 22 of said plates 11, 12 in order to define a half-turn zone for the fluids in each of the pairs of plates.

Referring once again to FIG. 2, it will be noted that the second unit 2 comprises at least one pair of terminating plates 12 a, 12 b, in said stacking direction D. Said pair of terminating plates 12 a, 12 b in this case comprises a plate 12 a, exhibiting a longitudinal extension that is identical to the other plates of said second unit 2 and a terminating plate 12 b exhibiting an upper longitudinal extension.

The upper terminating plate 12 b, in the given orientation in relation to the exchanger in this figure, comprises a protruding part 34 provided with openings, although not visible here, for the passage of the first fluid. Said openings enter into correspondence with the collectors 5 a, 5 b of the first unit 1. Said upper terminating plate 12 b may, furthermore, exhibit openings, similarly not visible here, for the passage of the second fluid towards the corresponding collectors 6 a, 6 b. Said exchanger in this case comprises one or more connecting flanges 36, 38 for the one and the other of the fluids, subject to said terminating plate 12 b in the area of said passage openings. In other words, said second unit 2 in this case comprises not only the one or more connecting flanges 38 for the second fluid, but also the connecting flange 36 for the first fluid.

According to a variant corresponding to the units illustrated in FIGS. 5 and 6, each of said units may comprise its own connecting flange 100, 200, as already mentioned, intended respectively to face the corresponding collectors 5 a, 5 b, 6 a, 6 b. Said pair of upper terminating plates of each of the units 1, 2 is then identical to the pairs of non-terminating plates.

In the one and/or the other of these embodiments, the lower terminating plate 12 b, which is still in the orientation depicted in FIG. 2, of the second unit 2 may comprise a protruding part 40, equipped with stamped end fittings 42 coming into contact with a part of the base of the collectors 5 a, 5 b of the first unit 1.

As illustrated in FIGS. 5 and 6, the invention relates to a further exchanger unit 1, 2 as described above, possibly equipped with a corresponding connecting flange 100, 200.

As will be appreciated from what has been stated previously, said one or more units are configured in such a way as to be capable of being inserted into a unit of the same configuration, with or without the same height of the blades 3, 4, by exhibiting a space 101, 102, open between said pairs of blades 3, 4, in the area of the longitudinal end edges 7, 8 of said blades.

Said units 1, 2 may be utilized according to the interleaved configuration already described or in other configurations, for example in the form, not illustrated here, of an exchanger comprising a housing for circulating another fluid and such a unit, positioned inside said housing, in such a way as to benefit from an exchange of heat between said other fluid and that circulating in said unit.

As illustrated in FIG. 7 for the first unit 1, said one or more units may be equipped with a spacer 110 between said pairs of plates 11. They may then serve, in particular, as exchangers with the air such as evaporators. 

1. A heat exchanger for a refrigerant circulating in a motor vehicle, said exchanger comprising: a first unit for circulating a first fluid defining first blades for circulating said first fluid; and a second unit for circulating a second fluid defining second blades for circulating said second fluid, said blades being layered in a stacking direction of said blades such that an exchange of heat can take place between said first and second fluids, said units permitting the first fluid to circulate while avoiding the second unit, and permitting the second fluid to circulate while avoiding the first unit.
 2. The exchanger as claimed in claim 1, in which said blades extend in a longitudinal direction, perpendicular to the stacking direction, and said first unit comprises collectors for the first fluid, situated in the area of a longitudinal end edge of the blades of said first unit, and/or said second unit comprises collectors for the second fluid, situated in the area of a longitudinal end edge of the blades of said second unit.
 3. The heat exchanger as claimed in claim 2, in which the collectors of the first unit are situated facing a longitudinal end edge of the blades of the second unit, opposite the longitudinal end edge of the blades of the second unit, in the area of which said collectors (6 a, 6 b) of the second unit are present, and/or the collectors of the second unit are situated facing a longitudinal end edge of the blades of the first unit, opposite the longitudinal end edge of the blades of the first unit, in the area of which said collectors (5 a, 5 b) of the first unit are present.
 4. The exchanger as claimed in claim 2, in which said units comprise plates, stacked in said stacking direction, said plates being paired in order to define said circulation blades, for each of the fluids.
 5. The exchanger as claimed in claim 4, in which the pairs of plates for each of the fluids exhibit a part protruding from the pairs of plates for the other fluid, in planes that are orthogonal to said stacking direction, in such a way as to be able to free up a zone of said plates, referred to as header plates, for receiving said collectors.
 6. The exchanger as claimed in claim 5, comprising fluid connections between the plates of the pairs of plates for a same fluid, situated in the area of said header plates, in such a way as to form said collectors, said connections being situated externally to the pairs of plates for said other fluid.
 7. The exchanger as claimed in claim 6, in which said fluid connections comprise stamped end fittings emerging from said plates, said stamped end fittings coming into contact with the stamped end fittings of the plate facing the neighboring pair of plates for the circulation of the same fluid.
 8. The exchanger as claimed in claim 6, in which said plates comprise a longitudinal end edge, referred to as the distal edge, opposite an opposing longitudinal end edge of said plates, in the area of which said fluid connections are situated, said distal edge being situated between two plates facing two neighboring pairs of plates for the circulation of the other fluid.
 9. The exchanger as claimed in claim 8, in which said distal edge of the plates of one of the units is in proximity to said fluid connections of the other unit.
 10. The exchanger as claimed in claim 8, in which said distal edge includes a part of the contour of said fluid connections.
 11. The exchanger as claimed in claim 1, in which the second unit comprises at least one pair of terminating plates, in said stacking direction, comprising a plate exhibiting a longitudinal extension that is identical with the other plates of said unit and a terminating plate exhibiting an upper longitudinal extension.
 12. The exchanger as claimed in claim 11, in which said second unit comprises at least one connecting flange for one of the fluids that is subject to said terminating plate.
 13. A heat exchanger unit as claimed in claim
 1. 14. The exchanger unit as claimed in claim 13 equipped with a spacer between said pairs of plates.
 15. A heat exchanger comprising: a heat exchanger unit of claim 13; and a housing for circulating another fluid, said unit being situated in the interior of said housing in order to permit an exchange of heat between the fluid circulating in said unit and said other fluid. 